Microdevices are manufactured by depositing and working several layers of materials on a single substrate to produce a large number of individual devices. For example, layers of photoresist, conductive materials, and dielectric materials are deposited, patterned, developed, etched, planarized, and otherwise manipulated to form features in and/or on a substrate. The features are often arranged to form integrated circuits, micro-fluidic systems, and other structures. Wet chemical processes are commonly used to form features on microfeature workpieces, clean the surface of workpieces, etch material from the workpieces and/or otherwise prepare the workpieces for subsequent processing. Wet chemical processes are generally performed in wet chemical processing tools that have a plurality of individual processing chambers for cleaning, etching, electrochemically depositing materials, or performing combinations of these processes. The processing chambers can accordingly be rinse/dry chambers, cleaning capsules, etching capsules, electrochemical deposition chambers, or other types of wet chemical processing chambers. Other processes, such as annealing, metrology, planarization, etc., are used to further process or analyze layers on the workpieces.
A typical wet chemical processing tool includes a housing or cabinet having a platform, a plurality of wet chemical processing chambers in the cabinet, and a transport system. The tool can further include separate robots that raise and lower a head of the processing chambers for loading/unloading workpieces. The transport system can have several different configurations. In a linear configuration, the transport system includes a linear track and a robot that moves along the track to transport individual workpieces within the tool. The transport system can also access cassettes or pods at a load/unload module.
Automated handling of workpieces is an important aspect of manufacturing microelectronic devices. In general, a robot must accurately move workpieces among different processing chambers and other stations within a single tool. For example, many robots move workpieces to/from six to ten processing chambers and two to three pods. A linear track robot typically moves the workpieces among the processing chambers and the pods by moving along the track, rotating one or more links about several pivot points, and raising/lowering the workpiece in a variety of complex motions.
One challenge of handling workpieces is accurately calibrating the transport system to move workpieces to/from the processing chambers and the pods. The transport system is calibrated by manually “teaching” the robot the specific positions of the individual chambers and pods. For example, conventional calibration processes involve manually positioning the robot at a desired location with respect to each chamber and pod, and recording encoder values corresponding to the positions of the robot at each of these components. The encoder value is then inputted as a program value for the software that controls the motion of the robot. In addition to manually teaching the robot the specific locations within the tool, the arms and end-effectors of the robot are also manually aligned with the reference frame in which the program values are represented as coordinates. Although the process of manually aligning the components of the robot to the reference frame and manually teaching the robot the location of each component in the tool is an accepted method for setting up a tool, it is also extremely time-consuming and subject to operator error. For example, it can take approximately six to eight hours to align a robot to the reference frame and teach the robot the locations of ten chambers and two pods. Moreover, the quality of each point input as a program value is subject to operator error because it is often difficult to accurately position the robot in one or more of the chambers or pods.
Another challenge of operating integrated wet chemical processing tools is repairing/maintaining the processing chambers. Electrochemical deposition chambers, for example, require periodic maintenance because they have consumable electrodes that degrade over time. Additionally, byproducts from organic additives can collect in the plating solution such that the processing solution is changed periodically. One problem with repairing or maintaining existing wet chemical processing chambers is that the tool must be taken offline for an extended period of time to replace the chamber and manually recalibrate the robot. In fact, when only one processing chamber of the tool does not meet the specifications, it is often more efficient to continue operating conventional tools without stopping to repair the one out-of-specification processing chamber until more processing chambers do not meet the performance specifications. The loss of throughput of a single processing chamber, therefore, is not as severe as a loss of throughput caused by taking the tool offline to repair or maintain a single one of the processing chambers.
The practice of operating the tool until at least two processing chambers do not meet specifications severely impacts the throughput of the tool. For example, if the tool is not repaired or maintained until at least two or three processing chambers are out of specification, then the tool operates at only a fraction of its full capacity for a period of time before it is taken offline for maintenance. This increases the operating costs of the tool because the throughput not only suffers while the tool is offline to replace the wet processing chambers and reteach the robot, but the throughput is also reduced while the tool is operating because it operates at only a fraction of its full capacity. Moreover, as the feature sizes decrease, the electrochemical deposition chambers must consistently meet higher performance specifications. This causes the processing chambers to fall out of specifications sooner, which results in taking the tool offline more frequently. Therefore, the downtime associated with calibrating the transport system and repairing/maintaining electrochemical deposition chambers significantly impacts the costs of operating wet chemical processing tools.
These challenges are not limited to operating wet chemical processing tools, but rather other tools face similar challenges. For example, wafers are moved to/from annealing and metrology stations using automated handling equipment, and thus it is time-consuming to align robots with these types of processing stations as well.
Another aspect of wet chemical processing tools is cost-effectively manufacturing and installing the tools to meet demanding customer specifications. Many microelectronic companies develop proprietary processes that require custom wet chemical processing tools and/or other types of processing stations. For example, individual customers may need different combinations and/or different numbers of wet chemical processing chambers, annealing stations, metrology stations, and/or other components to optimize their process lines. Manufacturers of wet chemical processing tools accordingly custom-build many aspects of each tool to provide the functionality required by the particular customer and to optimize floor space, throughput, and reliability.
To meet the requirements of each individual customer, tool manufacturers typically produce tools having a main processing unit with a platform configured for a specific number of processing chambers and/or other types of stations. Tool manufacturers must accordingly provide several different platform configurations depending upon whether the individual customers require 2, 4, 6, 8, 10, etc., processing stations in a tool. It is expensive and inefficient to manufacture a large number of different platform configurations to meet the needs of the individual customers. Therefore, there is also a need to improve the cost-effectiveness for manufacturing wet chemical processing tools.